I've gone before on Halloween and it's been great.
First off, the case for the civvies is understandable, but it's not as easy, or guaranteed, as it might seem, especially for those of us who don't live in a huge city and may or may not have a SO. It's not exactly cool if someone you know sees you out trolling a regular bar for ladies in that instance.
However, just like every other day, the club offers up the guarantee that you'll at least be able to see and feel the goods (for a price) while you still get the fun packaging of Halloween and can leave anything that happens within the four walls. Yes, you might lose some dancers to Trick-or-Treat, but it's still a Friday night and the clubs will still have plenty of talent.
Furthermore, I'm still waiting to strike gold one of these nights. A cheerleader costume -- and not a fake one, but a kind of realistic one, or the Dallas Cowboys cheerleader outfit -- or a naughty schoolgirl, or a naughty nurse, or a cowgirl ... yuh huh, gettin' all my money. Not into the generic dark makeup kind of thing or the girl who's a vampire or a zombie or whatever, but one of the above would really do it for me.
Best dance I ever got on Halloween was from a woman I thought was hot but a so-so dancer before. She was a classic rock chick for Halloween in ripped jean shorts and a ripped AC/DC T-shirt. Took her up on a dance and she had improved since the last time I got a dance with her. I also lucked out and the second song of our string -- this had to be a coincidence, the place was too big and there were too many others getting dances for the DJ to do this just for me -- was "Highway to Hell." She was into it big time and I reaped the benefits. Yup, good times.